Ceramic article and method of making same



UNITED STATES ra rENT OFFICE.

WALTER WILHELM HORN,.OF TEPLITZ, AUSTRIA, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO THE CHEMICAL FOUNDATION, INC, A CORPORATION OF DELAWARE.

CERAMIC ARTICLE AND METHOD OF MAKING SAME.

invented certain new and useful Improveproducing permanently durable ceramic ments in Ceramic Articles and Methods of radiators. It is true that such compositions Making Same, of which the following is a exhibited for the manufacture of ceramic specification. radiators at first very useful and agreeable The present invention relates to the use properties, but failed in the main require- 10 of fire-proof ceramic compositions for makment, that the radiators made from them ing radiators for steam and hot water shall also remain permanently durable, since h at rs, they went to pieces after a few months use.

The properties necessary in ceramic radia- Finally it was discovered that only compo-v tors are: (1) especially great resistance to sitions of the type of the so-called refractory 15 frequent changes in temperature, of course clay compositions, such as are used for makonly at temperatures of from 20 to 120 ing chamotte tiles, muffles, retorts and the at the most, (2), imperviousness to water, like, which must furnish resistance to the (3) high mechanical solidity, combined with highest temperatures used in the industries, l) a certain elasticity, exact shape, (6) actually furnish ceramic radiators that are 20 agreeable appearance, (7) easily cleaned (8) permanently durable. I surfaces capable of being glazed and (9) It is in the first place a very surprising fact comparative cheapness. that for making objects that are used only Hitherto it has not been possible to make within temperature limits of about 20 to ceramic radiators, that have shown them- 120, compositions must be used, that are 25 selves permanently resistant to change of otherwise employed only for producing obtemperature and also durable in use. The jects, that must resist the highest temperaceramie radiators heretofore used lasted a tures (li)00 (1., and far beyond) but in ad few months, it is true, but then began to dition to that comes the fact, that the reshow small cracks, that gradually enlarged maining properties of the objects made of re- 30 and spread through the entirebody of the fractory composition, their unattractive apradiator, so that the radiator at last became pearance, the fact that they contain shreds useless interspersed with strongly marked uneven In making up the composition ,to be used pores, their great perviousness to water, for making ceramic radiators, regard must their rough unglazed surface and moreover 35 be paid to that point first. Moreoverthe the known property of the refractory, firecomposition must be easy to mold. Since it resistant composition itself, of being moldis usual to place in the interior of ceramic able only under special circumstances, and radiators four or five narrow tubes and then only into simple bodies, must deter any make corresponding ribs on the outer surexpert from using such refractory composi- 40 face in order to obtain as'large a radiating tions for making radiators. Still the insurface as possible, in the least possible ventor has established the fact, that the proamount of space. In the case of iron radiduction of useful and permanently durable ators, it is extremely diflicult to produce such ceramic radiators is possible only in case of shapes, and accordingly the ceramic radithe use of compositions of the type of the so- 45 ators produced as described in the present called refractory clay compositions. These application possess material advantages, compositions however, in order to give the such as a saving of space. I also call attenradiators made of them in addition to pertion to the fact that in working in accordmanent durability also the other necessary ance with this process, it is necessary that properties, must be subjected to certain 50 the composition should be easily molded, and modifications. Firstly the material composhould be of a sufiicient degree of liquidity, sition, secondly the mode of mechanical to pour into the molds. production of the composition and thirdly Very numerous experiments, to discover the method of burning must beqaltered as the most suitable composition gave as a rewell as fourthly the objects must be capable 55 of being glazed. But all these changes must No Drawing.

To all whom it may concern: I

Be it known that I, WALTER -MAX WIL- HELM HORN, a subject of the King of Prussia, residing at Teplitz, Austria, have sult first, that not only dense ceramic com- Speciflcation of Letters Patent. Patented Mar, 30, 1920.

Application filed October 28, 1914. Serial No. 869,140.

positions, stone ware and porcelain, but also porous ceramic compositions, such as ordinary c-lay compositions, ordinary earthen ware and stone ware are entirely useless for 7 the addition of pulverized order to not afiect the fundamental requirement, that the composition shall be refractoiy, and suf-.

fractory clay compositions consists as a rule (made lean) by, chamotte, that of fire clay impoverished has been made from articles or shreds of fire clay, in various sized grains, in order that the composition shall be capable of being worked and the objeetsmade from it shall not warp or tear in drying and burning. The composition is made of these constituen'ts, while it is moistened with water and intimately mixed for example in a pugmill. The composition so obtained is mostly worked by molding or pressing, because compositions prepared according to the above principles liquefy only under peculiar circumstances and into simple objects.

The production of the compositions for ceramic radiators according to my invention on the contrary, is effected as follows: In order to obtain fine, pure colored radiators,

use fire clays burning as clean colored as possible, if necessary elutriated and impoverish them (make them lean) by-adding a chamotte of the same material. The chamo'tte is not used in various sizes of grain however, but only ,when pulverized to an even fineness. In the selection of raw.ma-

terials care must be taken that they shall.

contain as little as possible of free quartz, but much clay material, and secondly as few impurities and admixture of pieces of stone and the like as possible, which might act as flux. Such substances as feldspar must be carefully avoide The first requirement has its reason in this, that the ceramic radiators should be as finely porous as possible and that compositions containing muchclay material after burning present objects with much finer pores, than compositions with much finer quartz do. The object of the second requirement is to avoid the occurrence of the phenomenon of melting I burning by reason of the presence of flux, (alkalis and alkali earth compoundsin the materials used being especially to be avoided for this reason) whereby strains would 7 be produced in the comparatively large radiators, and such substances as alkalis and salts, which might become dissolved out of the material constituting the sections of the radiators by the water in the radiators, during the use of the radiators, would be accelerated by the repeated heating and cooling which would gradually lead to the destruction of the radiators. V In give the composition for ceramic radiatorsgreater capacity for molding and to give the finished radiators a still finer color, greater solidity and fineness of pore, a part of the chamotte may be replaced by can then be made only. up with water in ball sary for ceramic radiators,

which action tion for ceramic radiators has not only for' its purpose (as with ordinary fire clay compositions) in intimate materials, but is also to result, viz the comminution and liquefaction of the composition. For this purpose the constituents of the composition are ground millsto a determined mass which is easily molded, is obtained. The amount of water used in moistening the mixture of mater als, will be more than for moistening ordinary with 100 parts by weight raw materials, as abovedescribed, I may use 19 parts of water, in order to produce a comparatively thin mixture, which will readily flow; This mass, when molded produces ceramic radiators, having all the desired properties, which likewise have a very fineness whereby a clay, for example of the mixture of mixing of the raw.

is ord narily used fine even porosity. Special weight is laid i water. even pores are therefore absolutely neces-' because water has difliculty in penetrating the fine pores to begin with, but before all'these fine and even poresv can be completely andsurely closed by suitable glazing so that the radiators can be made entirely water-tight, the burning of the molded ceramic radiators also ifi'ers in many particulars ods followed in burning ordinary ceramic objects, thus while the ordinary ceramic objects pass through only one burning operation, but one as high as possible, ceramic radiators, to attain a faultless glaze, must be burned twice and in fact according to the Fine and from the methporcelain burning process they can be exposed first to a lower and then to a higher burning, or according to the stone-ware burning process first to the higher and then in the lower firing. .The h ighest burning temperature will not be driven over saggar cones 9-11 (1280-1320 mains below the highest temperature used 6.), so that it refor the burning of ordinary refractory ceramic ware. The ceramic radiators, at the temperature given if the compositions contain sufficient clay substance, attain both a suflicient solidity and a fine porosity by this comparatively low burning tempera ture. Thus fusion practically does not occur in burning these compositions, of which the starting materials are selected by the principles described above. The unavoidable differences in temperature at different places in the furnace, whereby various parts of one and the same radiator, might become heated to different temperatures, nevertheless cannot exert any unfavorable action, since the capacity of the raw materials of the radiator compositions to react upon each other at the temperatures used is very small. In consequence of this the possibilit of the production of internal strains in tlie com; paratively .large radiators, (whose dimensions are always considerable, in one direction and arise to heights of 1300 mm.) is substantially prevented. The hidden strains, which seem however to be present in all ceramic radiators made of other composition than those of the type of the fireproof clay composition, are however proba bly the cause of the splitting observed in ceramic radiators after only a months use. By the frequent heating and cooling of the previously known ceramic radiators during use, the hidden strains are probably released, there arise first small cracks, which gradually enlarge until they are present throughout the entire body of the heater and after a few months lead to the destruction of the radiator, on the contrary this phenomenon does not arise with ceramic radiators of composition herein described. Consequently they are permanently durable.

What I claim is 2-- 1. A refractory ceramic material, suitable for use in making heating elements of radiators, capable of sufficiently withstanding changes in temperature between 20 and 120 (3., said material contaimngplastic fire-clay,

- pulverized chamotte and lean kaolin, said ceramic material being substantially free from fragments of quartz and feldspar and being substantially free from alkalis and alkaline earths.

2. A burnt ceramic material, in the form of a heating element of a radiator, said element being capable of sufficiently withstanding changes in temperature between 20 and 120 C., said element containing as its essential constituents, plastic fire-clay, pul- "erized chamotte and lean kaolin, said material being capable of withstanding frequent changes in temperature, being slightly pervious to water, being of high mechanical strength, and possessing a sufficient degree of elasticity, and being unalterable in shape, and being capable of being glazed.

3. A refractory ceramic element for heating" radiators, composed of fire-clay, pulverized chamotte and lean kaolin.

4. A method of making ceramic articles which comprises intimately mixing and moistening a composition comprising fireclay, pulverized cha'motte and lean kaolin, with a relatively large amount of water, molding said composition, and thereafter burning the same, at a temperature not over 1320 C.

5. In the manufacture of ceramic articles, the step of firing a refractory ceramic article composed of fire-clay, pulverized chamotte and lean kaolin, at a temperature not over 1320 C.

6. In the manufacture of ceramicmaterials. the step of intimately mixing clays relatively free from quartz, feldspar, alkalis and alkaline earths, with pulverized burnt ceramic ware, to produce a mixture capable of giving a finely porous ceramic article, and thereafter molding said mixture into the form of hollow heating elements, burning the same and glazing the same.

In testimony whereof I affix my signature in presence of two witnesses.

WALTER MAX WILHELM HORN.

Witnesses:

CLARE SIMON, ILsE R. GRUND. 

